1. Field of Invention
The present invention relates to the separation of minor amounts of impurities from organic products such as glycols, glycol ethers, hydrocarbons and the like by an improved distillation procedure.
2. Description of the Prior Art
During normal preparation procedures, various oxygenated derivatives of organic products such as glycols, glycol ethers, glycol ether esters, hydrocarbons and the like, are formed in very small amounts especially at the elevated distillation temperatures which are normally employed in the production of such products. These impurities are frequently aldehydes, ketones, acids and the like and are undesirable in the product in that they impart characteristics such as malodor to the product.
Various methods are known for separating minor amounts of impurities, especially close boiling impurities, from various products including azeotropic and extractive distillation procedures but such prior methods are generally complicated and expensive. Steam stripping techniques have been employed but tend to result in the introduction of unwanted impurities with the steam, as well as producing water enriched products.
Stripping with inert gas, eg. nitrogen, produces a non-condensible stream which, if vented to the atmosphere would add to pollution, and if flared, adds a large load to the flare system. Also the inert gas does not enhance the volatilities of impurities.
Now, in accordance with the present invention there is provided a simple and effective distillation procedure whereby the separation of minor amounts of impurities is achieved.